//
/***********************************************************
             File name:      main.c
             Author:         Bitat (陆叁柒)
             Email :         Bitat@qq.com
             Gitee :         https://gitee.com/bitat
             CSDN  :         https://blog.csdn.net/bitat 
             History:        2023/3/31
************************************************************/
    

#include <stdio.h>
//小乐乐走台阶
int Fib(int num)
{
    if(num <= 2)
        return num;
    else
        return Fib(num-1)+Fib(num-2);
}

int main()
{
    int num = 0;
    scanf("%d",&num);
    int ret = Fib(num);
    printf("%d\n",ret);
    
    return 0;
}
